The present invention is directed to a manifold assembly for connecting a plurality of pumping units to a main line which in turn is connectable to a wellhead or the like. More particularly, the invention is directed to a manifold assembly which comprises a plurality of articulating arm assemblies which are each connected to the main line and extendable for connection to respective pumping units.
High pressure well service pumping units are commonly used in the hydrocarbon production industry to inject a variety of fluids into an oil or gas well during certain well servicing operations. For example, during a fracturing operation such pumping units are used to inject a particle-containing slurry into the well in order to fracture the hydrocarbon bearing formation and thereby produce channels within the formation through which the oil or gas may flow.
Typical fracturing operations require the use of several pumping units operating in unison to inject a large volume of slurry into the well. The pumping units are mounted on respective trucks or trailers which are parked close together, and the discharge pipe assembly of each pumping unit is connected to the so called main line of a collection manifold which is located on a separate manifold trailer.
The connection between each pumping unit and the main line is usually made using a temporary flow line comprising a collection of individual and pre-assembled pipes and swivel joints which are secured together by clamps or connectors. The flow line components are stowed on the truck or trailer in compact configurations, and when the truck or trailer reaches the job site, they must be unfolded and assembled in order to extend the flow line to the main line. However, this operation is time consuming, especially when multiple pumping units must be connected to the main line.
Also, in order to provide adequate support for the flow line, a common practice is to run the flow line from the truck or trailer to the ground and then from the ground to the collection manifold. However, this requires that each flow line be made up of several swivel joints comprising multiple swivel connections. In addition, the parts of the flow line which rest on the ground can experience undue wear that may shorten the life of these components. Furthermore, the numerous components of the many flow lines create cramped and cluttered conditions in the area between the pumping units and the manifold trailer, which can be a safety hazard for persons assembling the flow lines.
Furthermore, each flow line is typically connected to choke in order to create a pressure drop in the fluid flowing through the flow line and reduce pressure pulsations in the main line resulting from operation of the pumping units. The choke usually includes a fixed orifice choke insert which is mounted in a choke housing. The choke housing is normally connected to an isolation valve which in turn is connected to the main line. Thus, if the choke insert needs to be replaced, the choke housing must usually be disconnected from both the flow line and the isolation valve. Also, creating a desired pressure drop over a single choke usually results in a large amount of erosion in the isolation valve.